Kinetic Analysis Using Master Plot Method and Distributed Activation Energy Model for Non-Isothermal Pyrolysis of Heavy Oil

Global energy consumption has increased steadily and it leads to continuously increasing production of crude oils, major source of energy. However, the production of conventional oils becomes insufficient to satisfy growing demand for oil due to decreasing recoverable reserves. Eventually, conventional oils are likely to be exhausted in the near future. Therefore, it is expected that unconventional heavy oils such as oil sands bitumen, extra heavy oil, and heavy residue would play an important role to meet oil demand, because they have potential to be converted into more valuable light oils. As the production of unconventional heavy oils is increasing, upgrading technologies become increasingly crucial for its effective utilization. Pyrolysis process, which is one of promising upgrading techniques, can be efficiently used to produce useful light oils from heavy oils. Kinetic analysis is important for the development of pyrolysis process because pyrolysis behavior can be predicted through obtained kinetic parameters, and kinetic parameters are fundamental for modeling pyrolysis process and designing reactors. In this study, pyrolysis behavior of heavy oil was observed under non-isothermal condition with different heating rates using a thermogravimetric analyzer in order to understand pyrolysis characteristics of heavy oils. Also, a proper reaction model was determined based on the master plot method. Kinetic parameters (activation energy, pre-exponential factor, and standard deviation) of heavy oil pyrolysis were subsequently determined using a distributed activation energy model (DAEM). Using DAEM, complex pyrolysis reactions of heavy oils can be described with continuous activation energy distribution. In addition, the activation energies are represented by a distribution function of activation energy, f(E_a), for heavy oil pyrolysis.